Mississippian Culture and Aztalan

About the same time that Viking settlers founded colonies in Greenland and Canada, carriers of a new culture appeared in Wisconsin. Archaeologists call their culture "Middle Mississippian." About AD 1000, emigrants left the ceremonial center of Cahokia, across the Mississippi River from modern St. Louis, and built new towns in northern Illinois. Shortly afterwards, Middle Mississippians moved up the Mississippi and Rock River valleys into Wisconsin.

At its peak, between AD 1100 and 1200, Cahokia was a massive community with a population of between ten thousand and forty thousand (larger than London, Paris, or Rome at the time). The city centered on a vast, open plaza ringed by tall, flat-topped platform mounds and fortified by a massive palisade. Additional plazas, platform mounds, burial mounds, cemeteries, residential neighborhoods, workshops, and cornfields extended for miles in all directions.

Cahokia gave rise to a number of daughter communities across the upper Midwest. Their residents relied on corn agriculture, manufactured pottery tempered with crushed shell, and traded with their Woodland neighbors. Over a short span of time, the Middle Mississippians created a vast trade network that moved valuable items across the midcontinent and exposed Woodland peoples to Middle Mississippian culture.

Some of the most northern Mississippian outposts were in Wisconsin. The largest were located at the modern city of Trempealeau and at Aztalan on the Crawfish River (now a Wisconsin state park). The residents of Trempealeau built a ceremonial complex of platform mounds linked by a causeway on a bluff overlooking another platform mound in the valley below. Because excavations have been limited, archaeologists know little about this mysterious community.

Woodland peoples -- descendants of the local Effigy Mound culture -- had already settled the site of Aztalan. They were joined by Middle Mississippian immigrants, who transformed the village into a miniature version of Cahokia. The remodeled town boasted a central plaza, platform mounds topped with temples, and an elaborate fortification wall.

At both Aztalan and Trempealeau, archaeologists have found pottery that was made in Cahokia and then carried north. Excavations at contemporary sites across Wisconsin have documented cultural interaction between Woodland peoples and their Mississippian neighbors. Relations may not have always been peaceful, however. Excavations at many Middle Mississippian sites have uncovered evidence of warfare, and some Woodland and Middle Mississippian communities surrounded themselves with defensive stockades.

Aztalan and Trempealeau were abandoned by about AD 1200, around the same time that Cahokia slipped into decline. A new Mississippian culture, Oneota, began to expand across the Midwest, giving rise to many of the tribal groups known today. Many questions about this period remain unanswered. Although archaeologists debate the origins of these more recent groups, many believe that the Oneota culture arose out of the interaction of Woodland and Middle Mississippian peoples on the Cahokian frontier.

Today you can visit Aztalan, stand inside their re-created stockade, and climb their pyramids to imagine for yourself how people lived in Wisconsin ten centuries ago. The first European description of Aztalan was written by Nathaniel Hyer in 1837. Mistakenly thinking the platform mounds must have been related to Aztec pyramids in Mexico, Hyer gave the site its popular name. The first scientific examination of Aztalan was made by Milwaukee scientist Increase Allen Lapham in the summer of 1850. Since that time, many other archaeologists have visited and worked at the site, shedding light on a pivotal moment in Wisconsin's history.

[Sources: Birmingham, Robert A. and Leslie E. Eisenberg. Indian Mounds of Wisconsin (Madison, Wis.: University of Wisconsin Press, c2000). Theler, James L. and and Robert F. Boszhardt. Twelve Millennia: Archaeology of the Upper Mississippi River Valley (Iowa City : University of Iowa Press, c2003). The History of Wisconsin: volume 1, From Exploration to Statehood by Alice E. Smith. (Madison, State Historical Society of Wisconsin, 1973)]

Original Documents and Other Primary Sources

A visitor publishes the first description of Aztalan in 1837.

The second scholarly attempt to map and explain the mounds (1842)

An 1839 visitor credits Aztalan to ancient foreigners

A Mormon writer theorizes about the origins of Aztalan in 1845

The first careful investigation of Wisconsin mounds is published in 1838.